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Discussion of Natural Event Documentation High Winds, Corcoran and Bakersfield, California September 22, 2006. Rudolf B. Husar March 10, 2006. Key Evidence: High Winds -> High PM10. The SJV APCD makes a good case that high winds and high PM10 occurred in Corcoran & Bakersfield. - PowerPoint PPT Presentation
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Discussion of
Natural Event DocumentationHigh Winds, Corcoran and Bakersfield, California
September 22, 2006
Rudolf B. Husar
March 10, 2006
Key Evidence: High Winds -> High PM10
• The SJV APCD makes a good case that high winds and high PM10 occurred in Corcoran & Bakersfield
MODIS Terra, 10:30 Local Time MODIS Terra, 13:30 Local Time
MODIS Terra shows some pollution/smoke in the Southern SJV
MODIS Aqua, 3 hours later shows that the pollution/smoke has been cleared by the high winds
Neither image shows evidence of dust – not surprising since dust is hard to see over land
AIRNOW PM2.5, Sep. 22, 2006, Local time
• AIRNOW data are available along the SJ Valley
2006-09-22:14
2006-09-22:22
2006-09-22:16 2006-09-22:18 2006-09-22:20
2006-09-23:00 2006-09-23:02
AIRNOW PM2.5
• There is an issue with the absolute times – don’t match with the SJV report
Corcoran, 16:00 peak
Bakersfield, 20:00 peak
Modesto, 12:00 peak
Sacramento, ?? peak
The dust peak is progressing from 12:00 in Modesto to 20:00 in Bakersfield
Transport speed 0f 25 MPH would do it
Surface Visibility (Bext), Winds – Local Eastern Time ??
• The high winds were also ‘transported’ – moving southward• So, as the gust move southward it could create local dust wherever it peaks
2006-09-22:16 2006-09-22:18 2006-09-22:20 2006-09-22:22
NAAPS Dust Model, Sep 22, 2006 (Times are GMT)
• High surface dust concentrations are forecasted for California• In the early morning the highest winds & surface dust conc. Highest in N. California• By the afternoon, the winds & surface conc. highest over S. California
2006-09-22 00:00 2006-09-22 06:00 2006-09-22 12:00
2006-09-22 18:00 2006-09-23 00:00 2006-09-23 06:00
PM10-PM25 Obs from the SJV Report
• The PM10/PM2.5 ratio of 5-10 indicates fresh dust• But the broad peak in Bakersfield suggests that the dust there has been dispersed..
Tentative Conclusion
Tentative Conclusions• High winds were present to cause windblown dust• Short-term PM10 peaks are indicative of windblown dust• It was a Natural Dust Event
Questions
• Why is PM10 highest in Corcoran-Bakersfield? • Transport from the North is plausible
Alternative Speculative Explanation by RBH (may be off)
• The high wind gusts were moving southward
• As the gust progressed, it kicked up local dust and caused the very high PM10
•